1985 Johnson 140hp VRO 90 degree V4

[kenmyfam]

My lower unit I believe has been replaced with a V4 unit. I believe that this model came with a V6 gearcase. It appears that it has been replaced with a V-4 gearcase. It is 13 spline as opposed to 15 spline which I think is the V6 gearcase.
My question is, are they both the same length as my outfit came with the 140hp as standard but measuring it with more precision than i have previously (by eye alone) the cavitation plate is about a half inch below the bottom of the hull. I am thinking of jacking it up about 1 to 1.5 inches during the winter. Should give me a little less resistance and a little more speed. Currently I can power trim all the way up and use the power tilt a little before she starts to even think about cavitating.
What are your thoughts ????
Any and all responses are appreciated.
Thanks,
Ken

 

[ezeke]

Re: 1985 Johnson 140hp VRO 90 degree V4

The V6 type gearcases on the 140 X model looper motors were 15 Spline. The X model or 25" 140 motors had the same gearcase but with a different set of gears than the V6. Some of the older 25" V6 gearcases were 13 spline and will bolt on the 140 X loopers if you have the right shift rod.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

I suppose a photo might help eh !!!!

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

If it's 13 spline propshaft it's a V4 gearcase. It'll use the 13 1/4" or so props. The AV plate should not be below the keel no matter what case it is.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

Thanks for that. By eye I always thought it was a fraction above.....but today i checked it properly with the boat level and the trim at max up. (just before the tilt took over) It is in reality slightly lower. I will raise it an inch or so and see how it is when i go back in the water in spring.
It is a 13 spline gearcase and i am currently running a 14 inch diameter prop. It just makes it !!!
Should I go down a little in diameter ???? as well ????
Thanks for the input, it is much appreciated.
Ken.

 

[emdsapmgr]

Re: 1985 Johnson 140hp VRO 90 degree V4

As you raise the engine on the transom, you will increase engine rpm's-slightly. Each bolt hole you raise the engine should get you 3/4 of an inch. This change works well, but better if you have a good stainless prop. A good stainless like a raker or renegade bass will hold better (than any aluminum) running in elevated conditions. You may want to add a water pressure gauge to be sure you have good water pressure to the block as you do your experimenting.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

As you raise the engine on the transom, you will increase engine rpm's-slightly. Each bolt hole you raise the engine should get you 3/4 of an inch. This change works well, but better if you have a good stainless prop. A good stainless like a raker or renegade bass will hold better (than any aluminum) running in elevated conditions. You may want to add a water pressure gauge to be sure you have good water pressure to the block as you do your experimenting.

Thanks for the feedback. I am not really in elevated conditions where I am so will skip the pressure gauge at this time, however I will monitor the head temp, tell tale and waterflow when under way.
I would love a stainless prop.....but with the water levels the way they are around here currently, I would rather lose a prop than the lower unit so unfortunately will have to stick with aluminum. I dinged a prop Labour Day weekend at Conestogo Lake. The level had dropped 5 feet in a month and all the 3 ft depth markers were on their own private little islands !!!

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

The X dimension (AV plate height) is measured with the plate, or propshaft, parallel to the keel.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

The X dimension (AV plate height) is measured with the plate, or propshaft, parallel to the keel.

Thanks for that. I think that is how it was .....but I am going to check it again to make certain.
I will let you know what I find.
Ken.

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

The motor should be somewhere at about mid travel of the trim range. If you run a straightedge off the AV plate at max trim it will be way below the keel once it gets to the keel.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

The motor should be somewhere at about mid travel of the trim range. If you run a straightedge off the AV plate at max trim it will be way below the keel once it gets to the keel.

Thanks again. I will set the trim gauge to the centre and give it a visual as well. Then see what I have.
Just need some daylight now.
Will let you know what i find.
Thanks once again,
Ken.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

Well I checked it again this evening. Trim gauge at dead centre and a straight edge to the bottom of the hull. Dead level and even with the bottom. give or take a sixteenth of an inch. Will raise it an inch before the maiden voyage in spring and see what happens !!! that is unless someone else knows better !!! (and there are several of you out here)
Pleae give me your thoughts.
Thank You,
Ken.

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

Pay no attention to where the trim gauge needle is. You want the AV plate and propshaft parallel to the keel. It may or may not be in the center of the travel when the plate is parallel.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

It was parallel to the keel. I forgot to mention that. I did check that also. Happens to be that the gauge is dead nuts centre as well.
Thanks for the input. Any other thoughts as to what I should do height wise ?????
Thanks,
Ken.

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

Your actual final X dimension will depend on several things. Prop design, hull design, load distribution, overall set up and intended use etc. Testing is what will let you dial in any given prop on any given hull. Typically, once you get a given prop dialed in, folks tend to get a higher technology prop and start again. Always in search of that total efficiency.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

First thing I will do is raise her up an inch and see what I get. I am preety much against the high tech props as i live in an area of potentially shallow water. Standard aluminum prop is good so i will hopefully save the bottom end if the poop hits the fan !!!!!
Any thoughts ?????

 

[Dhadley]

Re: 1985 Johnson 140hp VRO 90 degree V4

Typically an aluminum prop won't allow as much of an X dimension as a ss prop. Nor will it tolerate as much positive trim. I'd still follow your plan though, raise the motor and test.

I don't subscribe too much to the theory of hitting bottom with a ss prop and ruining the lower unit. The aluminum and ss props have the same rubber cushion hub. The newer replacable hub systems won't spin like the old ones and they still don't have an issue. Yes, if you hit hard enough in a certain way it may tear up the gears but it's rare. I've been with a guy that we hit bottom so hard it broke the steering shaft. The gears were fine.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

Typically an aluminum prop won't allow as much of an X dimension as a ss prop. Nor will it tolerate as much positive trim. I'd still follow your plan though, raise the motor and test.

I don't subscribe too much to the theory of hitting bottom with a ss prop and ruining the lower unit. The aluminum and ss props have the same rubber cushion hub. The newer replacable hub systems won't spin like the old ones and they still don't have an issue. Yes, if you hit hard enough in a certain way it may tear up the gears but it's rare. I've been with a guy that we hit bottom so hard it broke the steering shaft. The gears were fine.

Thanks for the info once again. I am so looking forward to spring now. It will be a long winter waiting to see how it turns out.
You have made me think twice about a stainless prop now !! I know it is a little off topic in this section but I have good performance out of aluminum 14 X 17 (skiing with beginners and heavy folk and tubing) and a 14 X 19 for general purpose. Any suggestions on a stainless prop ??? or should I get the best case with the current props first. If it is going to get at all involved then I will start a thread in the prop section.
Thanks once again,
Ken.

 

[kenmyfam]

Re: 1985 Johnson 140hp VRO 90 degree V4

Bump....and finished winterising today, looks so sad with the winter cover on !!!...oh well roll on spring !!!!!